<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>单选按钮输入</title>
</head>
<body>

<form>
  <input type="radio" name="sex" value="male" checked>Male
  <br>
  <input type="radio" name="sex" value="female">Female
</form>

</body>
</html>